Winter fertilization: how to proceed

Winter fertilization of the vine or the lawn. How to analyze the soil to understand which fertilizers to add.

There winter fertilization serves to correct any development problems highlighted in the previous season. If by chance we have noticed that some vegetables have struggled more than expected or that the plants in the orchard have struggled to bear fruit, with proper winter fertilization we will avoid that the inconveniences can be repeated in the new harvest season.

Soil analysis before winter fertilization

But before proceeding with the winter fertilization 'Corrective' we need to know how our soil is made. Is it an acidic soil? Is it a basic-alkaline medium? What nutrients are you missing? To know for sure it is advisable to carry out a chemical analysis of the soil or better still a chemical-physical analysis, so we will also understand if we are dealing with a soil that is too loose or too compact, clayey or silty, sandy, peaty or humiferous.

Litmus papers are great for measuring soil pH and understanding if the soil is acidic (pH below 7) or alkaline (pH above 7). Alternatively, there are ph meters, which often also integrate other functions, such as the measurement of soil moisture. To assess the presence of nitrogen, phosphorus and potassium macroelements (the three main nutritional elements), a minimum laboratory analysis is required. It's an expense but it's worth it if we're not super-experts and want the most out of our crops.

Here is what we need and that we can buy directly online to perform a do-it-yourself analysis of the soil pH:

  • Litmus papers
  • Soil pH meter

The pH meter is more expensive but offers more careful readings. If you have a company that aims to obtain the certification ofbiological agriculture, a pH meter (digital pH meter) would be more suitable. If you have to take care of thewinter fertilizationof the home garden, albeit cultivated with the method ofbiological agriculture, litmus papers will suffice.

Once the ph has been identified, we can classify the soil:

  • strongly acidic (ph less than 5);
  • acid (ph between 5 and 6);
  • subacid (ph between 6 and 6.8);
  • neutral (ph between 6.8 and 7.3);
  • weakly alkaline (ph between 7.3 and 8);
  • alkaline (ph between 8 and 8.5);
  • strongly alkaline (ph higher than 8.5).

There are plants that are very demanding regarding ph, for example rhododendrons and heather that want a decidedly acidic soil, and others that adapt more easily. Knowing the ph value we can decide what to cultivate or correct the soil to adapt it as much as possible to the crops.

Soil laboratory analysis

If, on the other hand, we have decided for laboratory analysis (it is the best solution in the case of degraded soils or whose characteristics it is difficult to detect), samples must be prepared. For the test to be meaningful, a hole 40 cm deep must be drilled in three or four points of the ground. From each hole we will take three large pallets of earth that we will remove the stones, we will mix and deliver closed in a bag before it dries to the analysis laboratory.

With fertilizers it is possible to improve the soil by replenishing the missing nutritional elements, always bearing in mind that the pH value influences the availability of macroelements and microelements. The same function of fertilizers is performed by soil improvers and corrective agents as regards the physical and biological qualities of the soil.

Winter fertilization: when to do it

A difference between the winter fertilization and the spring one is that the results of the latter are more immediate. In spring it is fertilized to give the plants a vegetative sprint or to immediately correct contingent problems such as yellowing of the leaves. For this reason, foliar fertilization is also used in spring and summer, which has a faster action than that through the roots (the nitrogen absorption time by the leaves is only 3 hours) and microelements are administered as iron, zinc, copper and boron most often in liquid form (fertigation).

There winter fertilization instead it produces results that are seen after a few months. The characteristic is not the rapid effect but the persistence of the elements in the soil and the activation of biological mechanisms that lead to a soil rich in mineral salts and organic matter, also in synergy with snow, ice and microorganisms. There winter fertilization it is made with organic fertilizers to be mixed with the soil and is essential for the contribution of macroelements N, P and K (especially for the phosphorus that no plant can absorb through the leaves). The best time is from late autumn to early winter, so the substances will have time to act giving results in spring.

Corrective winter fertilization

The winter season which coincides with vegetative rest is, as we said, also the best time to correct the physical and chemical characteristics of the soil with soil improvers and corrective agents which in turn will facilitate the absorption of nutrients by the plants. Fertilizing, amending and correcting the soil are synergistic operations that have the common goal of providing plants with the nutrients they need in the best way possible, for this reason when it comes to winter fertilization often all three are meant.

Raising the pH of a very acidic soil is prohibitive (better to focus on an acidophilic cultivation) but if it is only weakly acid it can be corrected by calcitation. This operation consists in incorporating agricultural lime in the form of calcium carbonate at the rate of 200-300 grams per square meter and to be durable it must be repeated every two years. But be careful: the liming must never be done simultaneously with the winter fertilization with manure because the reaction between the two substances would nullify the advantages of both operations.

The opposite of calcitation is plastering, an operation that serves to lower the pH of too alkaline soils and which consists in adding gypsum or sulfur dust during digging. If we want to lower the pH of an alkaline soil, we must pay attention to the water used for watering, which is often very 'hard', ie calcareous.

Organic winter fertilization

The bestwinter fertilization of the soil is made with organic fertilizers, which enrich the soil with organic matter and, following complex transformations, combine to become humus. The classic organic fertilizer is manure (the best is horse manure together with cow manure) which must be used when ripe. Cornunghia and dry blood are also excellent organic fertilizers (both by-products of the slaughter of animals reared for food use). From the residues of the processing of preserved fish comes the fish meal, another excellent natural fertilizer.

On the market there are also various 'artificial manure' sold in bags that are more convenient to transport than natural manure. These are products which, unlike chemical fertilizers of synthetic origin, derive from the processing of natural substances and are obtained by mixing different organic substances and making them ferment. Sometimes they are in the form of pellets and are therefore called organic pellets.

Compost produced with home composting is also a natural fertilizer. According to the type and ripeness, compost can be used as fertilizer in the garden, in the vegetable garden and also at home.For the outside we can use ready-made compost (4-8 months of composting) while for the soil of potted plants mature compost is best (12-24 months of composting). Fresh compost (1-3 months of composting) can be used in the garden or vegetable garden, but it must pass at least one month before sowing or planting.

Winter fertilization of the vine

In the case of the vine, the period of the 'winter fertilization'It's autumn. From post-harvest to leaf fall it is in fact time to provide the plant with the essential elements with which to replenish its reserves. This is because the autumn weather conditions allow photosynthetic and radical activity, but above all because the vine has a particular functioning: from recovery to flowering it draws on the nitrogen reserves stored in its woody organs, absorbing little of it from the soil, and then replenishes in autumn. stocks. The vine also uses fertilizer in the cold season to better tolerate frosts.

Winter fertilization for the lawn

Even for the lawn, winter care coincides with a late autumn fertilization that must precede the frosts. To fertilize the lawn in autumn, slow release fertilizers based on phosphorus and potassium, which favor root development, should be preferred. Phosphorus acts on the roots, makes them more resistant and helps them to develop in depth; in this way the lawn becomes thicker and stronger. Potassium, on the other hand, makes the leaves harder and makes them resist the cold better. Nitrogen is more important in spring at the vegetative restart.

The fertilizer must be distributed evenly on the lawn with a fertilizer spreader (which can also be a seed spreader) taking care that the soil is not dehydrated during fertilization. After this operation and in the following days, the soil must be regularly irrigated. In the case of the lawn, chemical fertilizers (phosphatic, potassium, nitrogen or complex) are certainly more practical than organic fertilizer such as manure or compost; the alternative are organic fertilizers sold in granules.

Winter fertilization of citrus fruits

For the winter fertilization of citrus fruits you can take advantage of the properties of ground lupine, also suitable for organic farming. For all the info, please refer to the in-depth study: ground lupine.

Video: Fertilizing My Houseplants in Winter (December 2021).